Tire manufacturers have been developing tires for motorized vehicles that can sustain a puncture so that the tires may continue to carry the load of the vehicle for a short period of time. These types of tires will hereinafter be referred to as “run-flat tires.”
One prior art run-flat tire is comprised of more than one adjacent compartments, which are isolated one from the other by a separating wall, so that one compartment may continue to carry the load of the vehicle, even though another compartment is punctured and structurally fails. However, the intermediate separating walls are generally not reinforced, and therefore, a wall that is not reinforced suffers from overheating and deformation at points of high stress concentration. Consequently, such tires are suitable only for such vehicles as a jeep or a forklift that advance at a relatively low speed and develop a correspondingly relatively low stress concentration.
“Compagnie Generale d'Establissements Michelin”, Clermont-Ferrand, France, has developed a run-flat tire arranged such that a ring of hard rubber is secured to the wheel rim. If a tire structurally fails after being punctured, the ring engages the underlying road surface and carries the load of the vehicle. The vehicle does not provide a smooth ride when being supported by the ring, due to the low elasticity thereof. Also, the vehicle cannot advance quickly since the ring tends to overheat and to be torn. Furthermore, tire replacement is made difficult due to the addition of the ring, requiring the use of a specially designed apparatus for the replacement operation.
It is an object of the present invention to provide a run-flat tire which allows an automobile to continue to travel for a considerable distance, e.g. 200 km, without drastically reducing its speed after the tire has been punctured.
It is an additional object of the present invention to provide a run-flat tire which provides an automobile with a smooth ride after the tire has been punctured.
It is an additional object of the present invention to provide a run-flat tire that is made of the same materials and has the same dimensions as prior art tires.
Other objects and advantages of the invention will become apparent as the description proceeds.